Core for casting steel



(No Model.)

J. A. HBRRIe-K.

GORE FOR'GASTING STEEL.

Patented Aug. '7, 1883.

, INVENT'OR l ff v, v

ATTORNEYS .Illllllulllilll Illllllllulllllll.

WITNEssEs N. PETERS. Phalvthugmphar. Washington. )V C.

UNITED STATES PATENT OFFIC. y..

JAMES A. HERRICK, OF CLEVELAND, OHIO.

vcoma Fon CASTING STEEL..

.SPECIFICATION forming part of Letters Patent INC.Y 282,518, dated August 7 1883. Application filed April 21, 1882. (No model.) o

such as will enable others skilled in the art to which it-appertains to make and use the same.

My invention relates to cores foruse in casting hollow steel ingots; and it consists in the peculiarconstruction of the same, as will be hereinafter fully set forth and claimed.

In the drawings, Figurel is a longitudinal vertical section, taken through thecenter of my core and a mold. Eig. 2 is a view in section Heretofore cores have been made for casting various kinds of molten metal, in which hollowperforated core-irons havebeen used, such devices being covered with hay or straw, `and with loam, common earth, or sand, as described in Overmans Molder andwFoundenpageSQ, and in a practical `treatise onA casting and founding, (Spetson, pages`211, 212, and 213,)

`and in English Patent No. 88,338 of 1841;

but cores of this character cannot be used in casting opelrhearth steel, owing to its high temperature, which causes the material of which such cores are made to throw off such an `amount of gasl as to render it impossible for the volume to escape as fast as it is generated, the result of which is to leave in the casting what are termed gas-holes, and a further objection is that the earthy substance with which the outer surface of such cores is covered becomes fused in casting metals of a temperature equal to that of open-hearth steel, thus leaving upon the inner surface or surfaces of the casting a scale or glazing which cannot be removed, and which is injurious to the after-working of the metal, and to the metal itself.

I am also aw'are of the existence of a patent to`George (lowing, of March 4, 187 9, N o. 212, 902, in which there is described a core made bfsilica; but such cores cannot be used to advantage in the casting of metals of such high temperature as open-hearth steel, as in such cases the gas generated cannot escape without traversing the entire length of the core, which would not be possible with sufficient rapidity to prevent the formation of blow-holes in the casting.

My invention has for its object the removal of the objections above referred to by providing a core, the central portion of which consists of a hollow perforated core-iron, which is covered with pure or nearly pure silica, through which the gases pass to the hollow .core as fast as they are generated, the device being illustrated in the accompanying drawings. l

A is a hollow perforated tube, which is preferably made open at its upper and lower ends to allow of thefree passage of air through the same from bottom to top. This hollow pe1"- forated core-iron is provided with covering consisting of a mixture of pure or practically pure silica and a binder, whiclrmay consist of Hour-paste, glue-water, sour beer, or any other suitable substance containing no carbon, alka- .lies, metallic oxides, or other elements that would operate in the presence of excessive heat of molten, open-hearth, or other similar steel, to form a flux whereby fusion with the core would` occur, and thus cause a glaze or scoria on the interior of the casting.

In forming cores for castings 'having large apertures in them I prefer to increase the diameter of the core-iron to such an extent as to leave only sufficient room for a coating of silica sufficiently thick to resist the action of the metal upon the core-iron, but not so thick as to cause a serious obstruction to the passage of the gas through it.

I also prefer to use a wash consisting of finelypowdered silica, mixedwith a binder which contains none of the objectionable elements as above mentioned, it being only used to'iill up the rough and uneven surface of the core. The covering of silica over the hollow perforated piece allows ofthe escape of gases from the melted metal, but is impervious to the metal itself. Thus allowing of the escape of gases'ffrom the melted metal prevents or reduces the liability ofthe formation of blow-holes, and thesilica being a well-known refractory substance, and containingy no carbonfalkalies, metallic oxides, or other like elements, is the only practical coveringfor a core to be used in casting openhearth or like steels.

IOO

.J l @sans What I claim isp In testimony whereof have signed my name 4 In a core for use in casting steel, the eoinbito this specification in the presence of two subnation7 with@ perforated and ventilated center seribing Witnesses. piece7 of 2L covering consisting of a mixture of 5` pure or practically pure siliezt and a binder7 Witnesses:

substantially as and for the purposes shown W". E. DONNELLY,

` v J No. CROWELL, J r.

J AMES A. HERRICK.

and described. 

